This SBIR phase II proposal is aimed at developing microarray technology to study the interactions between heparan sulfate (HS) and proteins. HS is a highly sulfated polysaccharide displaying a wide range of biological functions. There is a strong demand in the research community for a high throughput method to study the binding between HS and proteins. During the previously funded phase I study (R41GM123792), Glycan Therapeutics has developed and launched a pilot HS microarray service. The outcome from the STTR grant clearly demonstrates that the research community greatly appreciates a convenient and reliable HS microarray service. This phase II application is focused on the expansion of the HS microarray service. Aim 1 is designed to expand the HS oligosaccharide library from 95 to 250 structures. A larger number of HS oligosaccharides on the microarray will enhance its ability to study the relationship between the function and structure of HS saccharide sequences. Aim 2 will develop a bioinformatic approach to structurally triage the oligosaccharides based on microarray data. The bioinformatic method is expected to predict additional structures that may interact with the target proteins. A streamlined website will simplify data presentation for end users to acquire the data without technical complexity. Our success will lead to a convenient and reliable research tool for advancing glycosciences.